Countersinking machine



April 29 w47 J. A. ROBERTS COUNTERS INKING MACHINE Filed septflo, 1940 2 Sheets-Sheet l m 'll ..111 11141 Illy.

JAMES A Poes/Q' 75- BY gvm/fg, M

' lATTRNEY April 29, 1947. J. A. RoBERTs 2,419,657

COUNTERSINKING MACHINE Filed Sept. l0, 1940 2 Sheets-Sheet 2 M wl f4 lllinimm I l 55 l l l j. v i .[35554] 2/4 f5 Z6) 54 Q w '7 R x f/ M @f1/fi; n ff v I INVENTOR JAMES A, ROBERTS 1 .5. BY v ATTORNEY i workmen.

Patented pr. 29, 1947 2,419,657 COUNTERSINKING MAcHmE James AfRoberts, Detroit, Mich., assignortohicago Pneumatic Tool Company, 4 New York, N. Y.,a corporation of Nervi-Jersey Application September 10,-1940,1Seria1N0. 356,163

rIhis invention relates to gripping and pulling machines adapted for usein metal working operations such as the forming of countersunk holes in sheet metal. One of the usesoi the invention is for operation on sheet aluminum forming the skin covering on the Wings and other parts of aircraft construction.

The machine of the invention has particular application as a means for preparing material for flush riveting operations, in which a rivet having a pre-formed flat head is inserted into the Work through a countersunk hole in order th'at the outer end of the rivet may lie flush or even with the surface of the work. Preparatory to thevriveting operation the countersunk holes are formed by pressing a metal working tool, or die, through aligned drill-holes in the adjacent sheets to be joined. The practice heretoforefolloWed of pushing the die through the work has an important disadvantage in that such a method requires that a. rigid support be held against the work on the underside thereof, or that side opposite to the one against which the dieholding tool is pressed. The rigid support is necessarily connected in some manner With the die holding tool, or must be manually'held by' one workman-While the die is driven into the metal by another workman. areas, such as the Wings of aircraft, lit is impractical to connect the rigid support to the die holder, and the secondof the above methods is generally unsatisfactory because of a .lack of uniformity and 'required skill on the part of the 'It' is proposed by this' invention'to introduce a new method of countersinking Whereinrthe die holder; and rigid support are embodied inj a single tool which is pressed againstone sideof the -Work and functions to pull, -or dra-W, th'e die -through or partly through the metal toward the stationary rigid support.

One objectof the invention is to obtain agrip- When working on largey .intothe die holder, prior to the gripping andpulling operation.

The invention, in the embodimenthereindisclosed, takesf-the-form of a portable pneumatic tool having independently operable gripping ,and pulling assemblies actuated in a determined sequenceunder th'eontrol of amanually operable l throttleyalve ,settable to a plurality fof ,control ping and pulling machine of simple and rugged construction which may be used in the forming of countersunk holes.

A furtherobject is to insure positive gripping of thedie before apulling movement-thereof may,

be effected.

A still further object is to place the gripping and -pulling mechanisms under the controlfof a Single -provision of. an-adjustable limit pin vdetermin- "ing i the distance.- which vthe die may: be inserted positions. a

Other objects and structural details of the invention will befmorc Vapparent :from the v,following description When readin k c )nju nct ion with the accompanying drawings,V wherein Fig 1 isa View partly in longitudinal f.section n and `partly in elevation of thetooloftheninven- .valve andthe pressureuid supply passagoswu 4V h it controls;

Figs. -aAand are.. detail viewssimil'ar toFia 2,y on a larserusoale, showing the f throttle vr volvo in longitudinal section, and indicating the respectivo popmol, ipiepmodiaia or partly aoii-1aiod., and the fullyactuatedpositions-.of the valve;

Aries.. 6,7.. and, 8 aredeiailedyiewa op. @larger vScalo :than Eie- 1i..ipf.1opsitodina1 .Sooiion, of the chuck mechanismofthe toolfaaiappoors;doripeztho Soi/ oral -stopsofy o ,oopnoerSipldpa9poration-Eig 6 showipaihoadie iosoroodin tho @ook mechanismboi f pot positively gripped thereby,

rig. '7 Showing the ports following aotuatiopfof the gripping meolianismppd, Fig. 8 Showinaihe vparts in fullyactuatod position ai the' ondof the pullingistrokoi-and y ffFies. 9 -andflO are dotoilrviews f showpg respetotively, a rivet inserted in acountersunlgholaand, t he: finished: connection;v made; by ppseitipg the :innerfendofy the rivet.

As shown in'pig; 1, the mam bodyof thema front and rear end plates fl 5 and mandan intermediate yplate l1 .positioned betweengi'eheend platesand acting to separate the chambers Cf--l vand'C--n-Z. Spacing ringsl and. |49, v supported between the respective .end plates' l5: and |63 and thefintermediateplate l1, ycomplete the formationfof-the front and rear compression chambers.

Aplurality of tie rods 2 I (one shown) ,extend b e- 4tvveen thev endplates y'l 5' and yI 6- and pass through the intermediate plate Il to .hold the assembly in a .i-lxed.v relationship. Th'e rear, end- -fplate ll-:has secured thereto apipe sectionzZZ which servesasV Reciprocable within the chamber C-2 is a pis-l ton 25 having a rod 26 secured thereto and disposed co-axially of the tubulardie 24. The rod 26 extends forwardly through the plates l1 and I5, passes through and beyond the boss 23, andv terminates within the tubular die 24 near the ,Y

outer end thereof. The front end of the piston rod 26 is formed with a circular recess 21 which is threaded and adapted to receive the threaded shank of a metal working toolin the form of a mandrel 28 (see Figs. 6, 7 and 8), inserted in the recess through the open outer end of the tubular die 24. When positively engaged in the recess 21, the mandrel 28 becomes, in eect, an extension of the rod,l or tool holder, 26, and, lupon rearward movement of the piston 25, is drawn into cooperative relation .with the stationary die 24. vIn-v using the tool to preparetwo or more sheets of metaliorriveting, the tool is held with the outer end of the die 24 pressed against one side of the work at a point substantially co-axial with aset of previously drilled aligned holes in the sheets. From the opposite side of the work the shank of the mandrel 28 is then passed through `the alignedfdrill holes and inserted into therecess 21. Then when operation oi the tool is initiated and the piston 25 begins to move rear- -wardly, the head 26a of the mandrel is drawn linto engagement withthe metal sheets and continued movement of the piston causes the mandrel'to eiect a countersinking action by forcing "inward that portion of each sheet lying within the periphery of the die 24. The working end -of the die 24 is formed with an inwardly tapered surface-29 which cooperates with-the head 28a, jjin the forming of the countersunk hole. Tofacilitate reception and gripping of the mandrel-2B, the front end of the piston rod 26 is formed as a chuck which has a slight radial resilience by reason of one or more longitudinal slots `3|,fformed therein. In the normal expanded positionof the chuck (Figs. 1 and 6) the recess '21 is of such diameter as to receive the shank of Ythe mandrel 28 with a clearance space preventing *positive engagement of the complementary threaded -portions on the mandrel and recess wall. To `effect such'positive engagement, the chucklike end of the piston rod 26 iscompressed, as a 'part of` eachcountersinking operation, to the gripping position of Fig. 7. `'llhe means for pressing the outer end-of rod 261into gripping position Ocompriserzs a sleeve 32 encircling the rod fora Lgreater portion of its length and having a sliding vvviit therewith.` The sleeve 32 lies between the pis- -ton`rodl26'and the tubular die 24 and extends 'rearwardly into. the compression chamber C-I whereY itis secured to a reciprocable piston 33. `The piston 33 is similar in size and general contourtotlie-piston 25 and is capable of independ- 'fent' operation to eiect movement of the sleeve '32rela'tively to the piston rod 26. c The front end ofthe sleeve 32 is formed with an inclined sur- "face` 34 cooperative with a complementary surface 35 on'the front end of the rod 26. Upon actuation Aof the piston v33, the sleevef32 is drawn rearwardly, relativelyto. the tool holder rod 26, and, through the co-action of the inclined surfaces 34 iand35; contracts the chuck-like outer end of rod 262i from the expanded position of Fig. 6 to the gripping position of Fig. 7. Following the operation of the p-iston 33 the piston 25 may be actuated to pull the rod 26 and mandrel 28 through a working stroke.

The pistons 25 and 33 are driven through their Working, or power, strokes by compressed air delivered to the chambers C-l and C Z under the control of a throttle valve, adapted, in one position, to admit air only to the chamber C-l, and, in another position, to admit air to both chambers C-I and C-2. The pistons are held in the normal position of Fig. l by respective yielding means which act to return the pistons forwardly at the end of the power stroke. The yielding means associated with the piston 33 is a coil spring 36 arranged within the chamber C-l between the rear face of the piston and the stationary plate l1. A similar spring may be used to return the piston 25 but a preferred construction is disclosed in which compressed air is used to exert a constant forwardly acting pressure on this piston. As shown in Fig. 1, the rear end plate i6 is recessed to form a chamber 31 in whicha piston 38 is positioned. The piston 38 is of a reduced diameter with respect to the piston 25 and is secured to a rearward extension of the piston rod 26.` The pistons 25 and 38 and rod 26 thus constitute an assembly vreoiprocable as a unit. One end o1" the previously mentioned pipe section 21 projects into the chamber 31 while the other, or outer, end `is adapted for connection with a pressure uid supply line (not shown) leading from a source of compressed air. Thus live air is directed constantly to the chamber 31 Where it acts on the rear face of the piston 38 to urge the assembly comprising elements 25, 26 and 38 to the normal position of Fig. l.

Considering now the means for conducting pressure uid to the chambers C-I and C--2 and for controlling the flow of such fluid, there is provided in the front end plate .l5 a passageway 39 and in the stationary plate l1 a passageway 4l, the two passageways opening respectively into the chamber C-l and the chamber C--2 at the front ends thereof. Respective conduits 42 and 43 are connected to the passageways 39 and 4l and communicate'with passages 44 and45 extending from a ,bore (Fig. 2) in the rear end plate I6. The bore 46 lies near the chamber 31 .ing 5l and has a head 52 lying below the lower end of the bushing and engageable therewith to prevent the now of air fromthe lower end of the bore upward to the passages 44 and 45. A compression spring 53, interposed between the head 52 and a cap 54 closing the lower end of the bore 46, presses the valve 48 toward closed position. Referring also to Figs.- 3, 4 and 5, it will be seen that the upper or stem portion of the valve 48 is hollow and is formed with three sets of ports 55, 56 and 51, permitting a flow of air to and from the interior of the valve, In the normal closed position of the valveiFigs. 2 and 3) the set of ports 55 lies outside the bore 46, above the bushing 5|, and so opens the chamber within the valve to atmosphere. The sets of ports-56 and V51iare normally positioned opposite (respectivebushing groovesE-and 59 communi- "arrasar l inally connected to exhaust, the airfbeing free .r

to flow from the/chambers to the interior of the vvalve 48 and outtoatmosphere through the ports. 55. vThe groove "59,- in ibushing 35 l isk 'actually Aa counterbore-extending through the lowerend lof the bushing-and adapted to receive, withV a-sliding f,

iit, a collar 53 formed on the valve 48 between lt'lieh'ead-52 `land the set of..ports"51. The Acollar 53 lifunctionsto prevent the flow of air from the groove15il through the ports 51 until thevalve dBi is-fdepressed a distancerv sufficient to place the .'po11ts`55 below the upper'erid-'of the bushing 5l.

.l .Ininitating operation lefthe tool the valve 48 is first depressed from thenor-mal positionof Fig. '3 vto the intermediate-position of -l'ig.4. Y This movement serves to-unseatthe valve head E2-'and :to place the collar 63'helow the lower endv ofthe bushing l. Live air-is then free to flowinto the groove. 59 and out; port i2-to the passageway "44 4where it-is directed to chamber C-I to actuate the .piston .33. 'Air may alsoflow from -groove 59 to the interior of valve 48 at .this time but cannot escape therefrom since the-:sets of portsr 55 and 55 lie out .of registry with the bushing grooves l.andhenceare closed. When-the-piston 33' has been'moved rearwardly sufficiently far to completethe vmandrel gripping'portion of the opera- .tion,:rthe valve 48 is depressed from the-intermediate position of Fig. 4 to the fully actuated position of Fig. 5. 'As a result of this additional movement the set of ports 55 is-brought-from its previous position above the .groove58 downward into registry with this Jgroove'and thereby establishes communication between the passageway '45, 4leading to chamber C'-'2, and theinterior of the valve'S. vIn this `position. of the throttle valve, air is directed from thegroove 59 into-passageway fli and'alsothrough the sets of ports 56 and 5l into valve 48'and out the ports 55 to the .passageway 45.y At this time,. therefore,vlive air entering bore e5 lmay flow simultaneouslyinto Lthe .pass'ageways 44 and 45 and is admitted vto `both chambersIC-I 'and C-2. .Bothpistons 25 .and 33 are thereby-actuated and. the entire grip- 'pingand pulling .assembly .is drawn rearwardly to ycomplete the .'countersinking operation. .The reaction of the air pressure on the plates I5 and H pushes the stationary die 24 forwardly' and holds thezfront end rmlyfagainst the work.. At the end ofthe power :stroke the operatingllever .e9 may be released, whereupon the valvel 48 .will be returned to normal by spring 53, and the chambers C-I and C-2 thereby opened. to the vatmosphere through. the.' ports and passageways leading to exhaust ports 55. I

In order that countersunk holes fof depth may be formed;there is provided, in the recess 21 (Fig. 1), anadjustable .limit vpin 64 .which determines the distance which mandrel 28 may be inserted into the'recess. vThe-pin 64 has a threaded engagement in the recess 21'and may be turned to causeiit to occupy a deeper or more shallow position in the recess. Since'the stroke of the piston rod- 26 is constanta variance in the position of the vmandrel head .28a with respect to the stationary die 24 will cause a greater orlesser penetration of the work by the mandrel. In Figs.v .l1-andl 10 .it is shown how a countersunk hole of the type formed by. thefpresenttool is used,Vv in driving rivets flush with theouterrsurface of the Work.v f A rivet Ahavi-ngl-a'iilat'l 'countersunkhead varying inserted into lthe ypreviously formed 'hole and "the inner lend4 vofthe lrivet is' lupsetby# va suitable vrivetingtool tol-forma tight -ttingfhead'lC 'on ift-he innerside of--thework The head/B fliesventirclyv within the countersunk-hole in the louter A'fs-heet"-offinaterial. I

- The 'method' fof countersinking -an'dV ush rivetlirig-aslherein described. lwhich includes thefstep of @inserting aicounters'inking tool through valigned l. A gripping and pulling assembly, the elements ofwhichare vdisposed aboutva common longitudin'al axis and include; ra'reciprocalolev tool "helder having a 'radially resilient chuck lat vone end thereof, a reciprocable sleeve Lsurmounting said tool'holder and operative upon movement irelative to said tool holder to contract said radi- .ally resilient chuck,and-independently operable fluid 'pressure pistons for actuating said sleeve landsaid-tool holder.

2..A gripping and pullingassembly, the ele- .ments of which` are disposed about` a common longitudinal -:axis, and include; a, reciprocable tool holder havingfaf-radially resilient chuck at one end thereof, la Yreciprocable sleeve surmounting said tool holder-iandoperative upon movement 1 relative tosaid toolrholder to -contract said radifally rresilient chuckla pair ofu pressure uid .operated pistons for actuating said tool holder-.and said sleeve, one loffsaid pistons being securedto .saidtool holder andthe other to` said sleeve, land -an.:additi'onal pressure iluidioperated piston se- .cured to.saicl.--tool-holder.r A

3. In :a gripping and pulling machine, the combination .of a-tool-holder having a chuck at one lend thereof and` reciprocable through -a-power stroke vand a return stroke, a reciprocable sleeve surmounting said tool holder and'operative upon movementrelative to said tool holder to impart Ya gripping action to saidchuck, a pair of pressure .fluid operated pistons for actuating said tool holder; means .for suppiying pressure fluid to one of said pair :of pistons in a direction to effect-a powerv stroke oflsaid tool holder, and means for supplying pressure fluid to the other of said pair .of pistons in a direction to elfect a return stroke of said tool holder.

4. In `agripping and pulling machine, the combination'of. arreciprocable tool holder having a radially resilient chuckpai; one end thereof, a reciprocable sleevesurmounting said tool-holder andil operative upon movement relative to said VIJapplieants Vrdivisiona1- application, Serial ANo.

Vrtool holderv to contract said radially resilient 'dependent means, said valve acting vwhen setin one position to admit pressure iiuid to one only of said.l means andacting wheniset in another posi- -tion to admit pressure fluid 'to both said means.

A' 5. A power tool for countersinking metal sheets preparatory to riveting, comprising a die forming an integral part of the.v tool and adapted to be -pressed 'against one side of the work with a cen- .tral opening therein in registri7 with a drilled hole in the work, a removable die having a stem which is passed through the drilledhole from the lopposite side of the work and inserted into said inte'gral die, the adjacent faces of said dies lying 'on opposite' 'sidesY of the work and fbeingformedvvith complementary surfaces one of which is concave and the other of which is convex, a chuck embodied in the tool for gripping the stem of said removable die following its insertion in said integral die, fluid pressure means for actuating said chuck into gripping engagement with said stem, and fluid pressure means for moving said chuck in a directionto pull said removable die toward the work and for applying simultaneously the reaction of said force to said integral die in a direction to press it toward the work, said dies being thereby squeezed together to form a dimple in the intermediate sheet or sheets constituting the work.

6. A power tool for countersinking metal sheets, comprising a motor housing in the form of a cylinder, tubular extensions of reduced cross-section projecting from the opposite ends of said cylinder, the rearward of said extensions serving as a handle for the tool and the forward of said extensions being adapted to be brought to position surrounding a drilled hole in the work, a die at the outer end of said forward extension and having a central opening adapted to register with the drilled hole, said die forming an integral part of the tool, a removable die on the side of the work opposite said integral die and engageable with the work while a stem thereof is passed through the drilled hole and inserted into the integral die, the adjacent faces of said dies lying on opposite sides of the work and being formed with complementary surfaces one of which is concave and the other of which is convex, a chuck reciprocable within said forward extension and operable to grip andpull the stem of said removable die, a fluid pressure operated piston Within said cylinder and operatively connected to said chuck to effect operation thereof, means for introducing pressure iiuid into said cylinder to actuate said piston and apply the reaction of such force to said integral die in a direction to press it against the work, said dies being thereby squeezed together to form a dimple in the intermediate sheet or sheets constituting the work, and a throttle valve controlling the flow of pressure fluid and mounted adjacent said handle for convenient manipulation by the hand of the operator.

7. A power tool for countersinking metal sheets, comprising a motor housing in the form of a cylinder, a tubular extension of reduced crosssection projecting -forWa-rdly from the cylinder and adapted to be brought to a position surrounding a drilled hole in the work, a die at the outer end of said forward extension and having 'a' central opening adapted to register 'with the drilled hole, said die forming an integral part of the tool, a removable die on the side of the work opposite said integral die and engageable with the work while a stem thereof is passed through the drilled hole and inserted into said integral die, telescoping shafts longitudinally movable within said forward extension, the inner of which shafts constitutes gripping and pulling means cooperable with the stem of said removable die, the outer of said shafts functioning to press said gripping and pulling means into gripping engagement with said stem, first and second iiuid pressure pistons aligned within'said cylinder and operatively connected respectively to said outer and inner telescoping shafts, means partitioning said cylinder into front and rear piston chambers respectively accommodating vthe first and second said pistons, the inner of said shafts extending longitudinallyl through said first piston chamber and said partitioning means into said second piston chamber, means for supplying pressure fluid to said piston chambers to eifect operation of said pistons and apply the reaction of such force to said integral die in a direction to press it against the work, said dies being thereby squeezed together to form a dimple in the intermediate sheet or sheets constituting the Work, and means for controlling such fluid supply to initiate operation of said pistons in a determined sequence.

8. A countersinking machine according to claim 1, characterized in` that said integraldie, said motor housing and the partitioning means therein are held against relative movement and so arranged that the reaction of the iiuid pressure exerted lupon said `pistons tends to pressV said integral die against the work.

9; A countersinking machine according to claim 1, characterized in that said means for controlling thesupply of pressure iiuid to said piston chambers comprises a throttle valve settable to one position to `prevent the passage of fluid to either of said chambers, settable to a second position to admit fluid only to said front piston chamber, and settable to a third position to admit huid to vboth said chambers.

l0. A power tool for countersinking metal sheets, comprising a die forming an integral part of the tool and adapted to be pressed against one side of the work with a central opening therein in registry with a drilled hole in the work, a removable die having a stem which is passed through the drilled hole and said integral die from the opposite side of the work, the adjacent faces of said dies lying on opposite sides of the work and being formed with complementary surfaces one of which is'concave and the other of which is convex, a reciprocable chuck into which said stem is inserted following its passage through said integral die, means for initiating gripping and pulling motions of said chuck to draw'said removable die toward the work, said meansreacting in a direction to press said in- .tegral die toward thework, whereby said dies are squeezed together to form a dimple in the the opposite side of the work and inserted into said means reacting' in a direction to press said integral die Vtoward the work, whereby saidy dies are squeezed togetherto form a dimple in the intermediate sheet or sheets constituting the work, and fluid pressure control means adjustableinanually--from anormal position successivelyto-partly actuated and'to fully actuated 9 positions thereby to complete a countersinking operation in separate stages each initiated at the Will of the operator.

12. A power tool for countersinking metal sheets, comprising a die forming an integral part of the tool and adapted to be pressed against one side of the work with a centralv opening therein in registry with a. drilled hole in the Work, a

removable die having a stem which is passed through the drilled hole and said integral die from the opposite side of the Work, the adjacent faces of said dies lying on opposite sides of the Work, one of said die faces being frusto-conical and tapering towards the other die face, said other die face having a central recess surrounded by an annular shoulder adapted to abut against the metal sheet, a reciprocable chuck intovwhich REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,047,341 Vaughn et a1. July 14, 1936 1,857,754 Hall May 10, 1932 953,295 Riehl Mar. 29, 1910 2,114,289 Draim Apr. 19, 1938 2,147,763 Becker Feb. 21, 1939 1,892,712 Taylor Jan. 3, 1933 1,897,320 McKnight et al.'- Feb. 14, 1933 558,072 Higgins Apr. 14, 1896 1,656,736 Kellogg Jan. 17, 1928 Re. 3,966 Regan May 10, 1870 577,063 Pedersen Feb. 16, 1897 1,756,773 Wendt Apr. 29, 1930 2,155,634 Baxendale et al. Apr.f25, 1939 2,268,849 Salisbury Jan. 6, 1942 1,911,653 Taylor May 30, 1933 1,455,440 Honger May 15, 1923 2,292,446 Huck Aug. 11, 1942 2,088,859 Huck Aug. 3, 1937 2,132,113 Huck Oct. 4, 1938 Certiicate of Correction Patent No. 2,419,657; April 29, 1947.

JAMES A. ROBERTS It is hereby certified that errors appear in the printed speciieation of the above numbered patent requiring correction as follows: Column 8, line 13, claim 8, and line 20, claim 9, for the claim reference numeral 1 read 7 and that the said Letters Patent should be read With these corrections therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 1st day of July, A. D. 1947.

LESLIE FRAZER,

First Assistant Commissioner of Patents. 

